Designing Linear PAs at Millimeter-Wave Frequencies Using Volterra Series Analysis

Power amplifiers (PAs) at millimeter-wave (mm-wave) frequencies are required for delivering high output linear power while being efficient; however, their performance is severely affected by the scaled semiconductor technology and the operating frequency. To improve the linearity of mm-wave PAs, it is recommended that an external linearization technique such as predistortion be used. The PA presented in this paper uses adaptive predistortion (APD). The APD linearization technique was developed using the Volterra series analysis on the silicon-germanium (SiGe) heterojunction bipolar transistor. The Volterra series analysis was used to identify and characterize the third-order intermodulation distortion components. The PA uses a single-ended common-emitter topology. It consists of three stages biased in the Class AB mode. The PA and APD were designed using the 130-nm SiGe bipolar and complementary metal-oxide-semiconductor process. The PA and APD achieve an optimum third-order intermodulation reduction of 10 dB and an improved linear output power of 2.5 dBm.